Manufacture of ingots.



W. H. GONNELL.

MANUFACTURE 01? INGOTS.

APPIIOATION FILED JULY 10, 1912.

074 24 I Patented Sept. 30,1913.

WITNESSES. [NVENTOR ingot a short distance below the shallow cooled byreason of'contact with the wall of WILLIAM H. CONNELL, or r rrssunen,PENNSYLVANIA.

MANUFACTURE OF INGOTS.

' Specification of Letters Patent.

Patented Sept. 30, 191$.

Application filed July 10, 1,912. Serial No. 708,712.

To all whom, it may concern:

Be it known that I, WILLIAM H. CONNELL. residing at Pittsburgh, in thecounty of Allegheny and State of Pennsylvania, a citizen of the UnitedStates, have invented or discovered certain new and useful Improvementsin the Manufacture of Ingot-s, of which improvements the following is aspecification. i

As is well known in the art, the piping in the upper portions of ingotsis a source of considerable loss. This piping is due, to a very greatextent, to the solidification of the outsides and the upper end'of theingot while a large interior portion remains molten or plastic andinsuflicient in volume when'solid to fill the ingot outlined by theearlier solidification of the outside and top. It has been attempted toprevent this piping by the application of heat to the upper sur face ofthe metal in the mold. But it has been found that the heat so applied iseffective to keep the metal in a molten condition for a'veryinconsiderable depth and that a bridge of metal will form across thebody of molten metal. It has also been proposed to place an electricallyheated sleeve on the end of the mold adapted to contain sufficient,metal to fill the cavities formed during the solidification of the metalin the mold proper. This compensating body of metal is maintained for asuitable time in a liquid condition to fill in the cavities, and suchportion of metal as remains in the sleeve or sinker-head after the metalin the mold has solidified, is removed from the ingot orother article.Although in this in stance the sleeve is heated sufiiciently to maintainthe metal inclosed ina molten condition, its effect does not extend toany greater depth than where the heat is applied to the surface of themetal in the mold.

It is well known that during the solidification of the metal in a mold,changes are taking place due to segregation, and hence those portions ofthe ingot which are first the mold will differ materially from the innerportions which solidify more slowly. As for example it is well knownthat during solidification uncombined carbon is will rise to the upperor other article. As t portions of the ingot e carbon content of asstated near the .metal influences to a very considerable dewill tend tohasten the cooling of such portions, and par-passu will render theportions from which the carbon has moved less sensitive, and hence therewill be such a reduction of plasticity or partial solidification ofportions adjacent to the upper part of the ingot while lower interiorportions are still fluid, that the escaping from the fluid portions,will be trapped by the same plastic bridge formed top of the ingot. Andfur'ther'it is believed that the presence of this bridge near the .upperend, prevents the metal kept fluid by the methods hereto fore employed,from flowing down into blow holes due to trapped gases or cavities dueto shrinkage below the bridge. p

As piping is due to the. outward movement of metal to the shell formedagainst the wall of themold, it is obvious that by 'preventing thesolidification of the outer portions of the ingot in advance of that ofthe interi rport-ion the formation of cavities from such cause will beprevented. But

in none of the methods heretofore proposed there been any attempt toprevent the formation ofpiping but only to fill them in after they areformed.

The invention described herein has for its object the provision of meanswhereby.

the rate of cooling and solidification of any desired portion, may beretarded and regulated that the resulting ingot may be solid throughoutwithout pipes or vacuities.

The invention is hereinafter more fully described and claimed.

gases generated in or In the accompanying drawing forming a part of thisspecification, Figure 1 is a sectional elevation showing ingot moldshaving my improved heat generator in position;

Fig. 2 is a similar view showing a modification of the heater; Fig. 3 isatop plan view of the form shown in Fig. 1; Fig. 4 is a top plan view ofa mold and heater, the latter adapted for use with a three phaseelectric supply; Fig. 5 is a plane development .of the heater shown inFig. 4.

Inthe practice of my invention I employ an annular heater formed of somesuitable refractory material as fire-clay,

magnesite, etc. vWithin the walls of this annular heater is embedded anelectric eonductor capable of beingheated to a high temperature,'z'.e.,' above that of molten steel 'without being destroyed or injuriouslyaffected. In the heater shown in Fig. 1, the conductor 2 is of a helicalfor'm', having its opposite ends connected to terminals 3, which areadapted to be connected to a supply of electrical energy. This form ofeater can be conveniently formed in two parts fitting one into the otheras shown in Fig. 1. The outer face of the inner section is grooved forthe reception of the conductor 2, and after the latter has been placedin position the two sections are fitted together.

In the heater shown in Fig. 2 the resistor is in such form as to beeasily ada table for not suflicient to submerge it to the desired.

'use with single phase or poly p ase electrical supply." Fig. 5 showsthe arrangement for a 3-phase sup ly. 4

When casting ingots t e mold will be filled up to the desired level andbefore the upper surface has materially chilled, the heater which hasexternal dimensions less than the internal dimensions of the mold isplaced in position. If the weight of the heater is depth weights may beplaced thereon, or it may be forced down by any other suitable means. Asa heater is annular it may be placed in the mold prior to or at any timedurin the teeming of the metal and the entire c arge or any portion. ofthe metal poured in through the heater which will be moved up as themetal rises, such movement being preferably due to the buoyancy of theheater. It is preferred that the heater should be raised to hightemperature before being placed in the mold, in order to prevent achilling of the metal in contact therewith. It will be understood thatthe heater can be raisedto a temperature higher .toward the heater, andat the same time the heater will be gradually raised from the metal. 7This removal of the heater is facilitated by making thewall of theheater wedge shape in cross-section.

' It will be observed that the heater is substantially smaller than themold so that there will be a considerable body of metal between theheater and the inner surface of the mold and that this bodyof metal willbe subject'to the heat radiated .from the heater. The temperature of theheater can be so regulated that the chillin effect of the wall of themold can be modi ed to such an extent that the outer portions of themetal will have more or less plasticity. As

' before stated the heater canbe placed in the mold at any time and atany desired height and then by regulating its upward movement, thesolidification 'will occur progressively upward across the entire-mass.

As the coolmg will be approximately uniform across the ingot theshrinkage will be of the mold. It is probable that the metal immediatelyin contact with the mold may become somewhat harder than the interiorportions, but the heater can be so regulated that the metal in contactwith the'mold will be at least plastic.

As set forth in the English Patent No.

3501 of 1884 to Ellis, it has been proposed to form solid ingots byarranging a refractory sleeve in the upper end of the ingot mold andfill not only the, mold but the sleeve with the molten metal. Heat isthen applied externally to this refractory sleeve so as to maintain themetal therein in a molten condition, until after the metal in the ingotmold proper has solidified. The mold with the refractory sleeve chargedwith molten metal is then removed and the metal in the: sleeve allowedto solidify. During this solidification the surface metal at the upperend of the sleeve becomes hardened and there will be formed a pipe as inthe usual casting method. The mold and sleeve are then removed and themetal in the sinker-head cut off from the ingot.

In the invention described herein the mold is charged with onlysufficient metal to form an ingot of the desired size. Heat is thenapplied to the molten metal in such manner. as to keep the metal incontact with the mold from complete solidification until after theinterior portions of the ingot have-at tained approximately the sametemperature. It is also characteristic of. the'invention de-- scribedherein that the surface metal at the upper end of the "ingot ismaintained in a molten condition until after the lower tion of-the'ingot has solidified.

. I claim herein as my invention:

1. Asan improvement in the method of porforming solid ingots, the methodherein described, which consists in teeming mto the mold only the amountof metal desired'in' the finished ingot, applying suflicientheat to themetal in the upper portion of the ingot in such manner that it willmaintain such upper portion including'the metal in contact with theinner surface of the mold in a plastic condition, during thesolidification I of the'lower portion of the ingot. f

2. The improvement in the art of formin ingots, etc., the method hereindescribed which consists in teeming metalinto a mold, bringing suchmetal to an approximately even temperature transversely "of the mold,-

and permitting the progressive solidification upwardly while malntainingthe transverse uniformity of temperature.

3. The improvement in the art of form- 5 ing ingots which consls themethod herein described ts in maintaining a substantial portion of theupper partof an ingot at a temperature of the metal not less than themelt' g point during the solidification ofthe lower portions of theingot and permitting 10 of the progressive upward cooling andsolidification of such upper portion;

' In testimony whereof, I have hereunto set my hand. WILLIAM H. CONNELL.

Witnesses:

M. K. Cosme, F. E. WILEY.

